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Abstract
Numerous populations from six spruce taxa, including four relict endemics,
Picea chihuahuana (Chihuahua spruce),
P. martinezii (Martínez spruce),
P. mexicana (Mexican spruce), and
P. breweriana (Brewer spruce), and two widespread species,
P. engelmannii (Engelmann spruce) and
P. pungens (blue spruce), were compared at homologous isozyme loci to test various hypotheses about their afŽfinities and origins. Each of the species was clearly separated, and Neighbor-Joining and Unweighted Pair Group analyses of Nei’s genetic distance grouped all populations within a taxon into their own clusters. Spruces from Flys Peak, Chiricahua Mountains, Arizona, joined a
P. engelmannii cluster and were not a bridge to
P. mexicana as previously believed. Spruces from Cerro Mohinora, Chihuahua, were clearly
P. mexicana, not phantom hybrids of
P. chihuahuana and
P. pungens. Nuclear random ampliŽed polymorphic DNA and chloroplast simple sequence repeat and cleaved ampliŽed polymorphic genetic markers were compared in a smaller sample of populations, using distance and parsimony approaches. DNA markers, like isozymes, clearly identiŽed spruces from Cerro Mohinora as
P. mexicana.
Citation
Ledig, F. Thomas; Hodgskiss, Paul D.; Krutovskii, Konstanin V.; Neale, David B.; Eguiluz-Piedra, Teobaldo. 2004. Relationships among the spruces (
Picea, Pinaceae) of southwestern North America. Systematic Biology 29(2):275-295
